You can download the checklist from the After Watchmen... What's Next? site.
Other than Identity Crisis (because it's Identity Crisis), I've read everything on the checklist in either trade or singles format. I'm... vaguely proud of that, I guess? Especially since I read the vast majority of them after reading Watchmen! In 2002, but still!
I've read less from the individual categories (I completely forgot Albion existed, for instance), but still have a pretty good showing there, although reading that Heroes collection will probably count against me karmically. There was some halfway decent stuff in there, though, I swear! Of course, I still gave a crap about Heroes back when I read it. Ah, how naive I was in the summer of '08.
Oh, and I'm just posting this now because DC sent me an e-mail reminding me of the the list/site's existence.
Special Overindulgent Bonus: All Of The Comics Listed On The Site That I Have Read:
Saga of the Swamp Thing vol. 1 (have volume 2, too; need to get on finishing that)Batman: The Killing Joke (Got in the Complete Alan Moore DC Experience trade, or whatever that thing was called)Planetary vol. 1Ex Machina vol. 1All Star Superman vol. 1 (Have the whole run in singles)Superman: Red SonArkham AsylumKingdom ComeAnimal Man vol. 1 (and vol. 2 and 3)Top Ten vol. 1 (and vol. 2)HeroesBatman: The Long HalloweenBatman: Year One52 vol. 1 (1-4 and the companion, actually)DC: The New Frontier vol. 1 (I have the Absolute Edition!) JLA vol. 1 (read all of it in some form, only own like 3/4 of it)Doom Patrol vol. 1Batman: Hush vol. 1 (in singles. I regret it to this day)DC Universe: The Stories of Alan Moore (that's what this is called!)Superman For All SeasonsSeven Soldiers vol. 1 (all of it in singles)Authority vol. 1 (have all of Ellis and Hitch's run in trade)League of Extraordinary Gentlemen vol. 1 (got volume 2 in singles)Promethea vol. 1V For VendettaTom Strong vol. 1 (in singles)We3Invisibles vol. 1 (still need to finish this; to be honest, haven't seen it since I moved)Global Frequency vol. 1 (in singles)Sandman vol. 1 (and the two collections that are short story collections, pretty much, which could be why I can't read Gaiman any other way)Y: the Last Man vol. 1 (and vol. 2; liked it okay, but it's no Runaways)RoninTransmetropolitan vol. 1 (and vol. 2, from Sci-Fi Book Club. Liked it a lot, intend on finishing it at some point)Preacher vol. 1 (one of the few comic runs I own all of in trades)Fables vol. 1 (was pretty indifferent to this one, never read future installments to see if it would get better; wound up giving it to Greg Hatcher in exchange for Sebastian O, actually)Losers vol. 1 (I am really bad at following up on these things)It's a Bird (Great, great book; well worth picking up)The Filth vol. 1 (I really wasn't in to this, except for Greg Feeley's cat)Orbiter (one of my least favorite Ellis stories, although it wasn't bad, per se)The Quitter (Harvey Pekar's greatest hits convinced me I didn't need to read any more Harvey Pekar, but it was nice seeing Dean Haspiel's art in that format)Sloth (great GN from Gilbert Hernandez; well worth reading if you haven't picked it up)Stuck Rubber BabyDemo
So, I'd say that's a fair cross section of what DC has to offer that I own. Feel free to post your own list if you bothered to read this far and want to share.